Spiritual formation, becoming more like Jesus Christ in thought and deed, requires a renewed mind (Romans 12:2) that avoids worldliness (1 John 2:15-17) and pursues godliness (Matthew 5:1-18; 6:33). Our sanctification through the Holy Spirit requires an ongoing dependency on God. We are to grow in the knowledge of God and of the workings of his Kingdom (Matthew 6:33). We are to see ourselves (James 1:25), our place in the church (1 Corinthians 12-14), and the broader culture (1 Chronicles 12:32) in light of his Word.
To this end, here are some principles and recommendations in how to “take every thought captive to obey Christ” (2 Corinthians 10:3-5).
Remain faithful in the reading and study of the Holy Scriptures, which are God’s cognitive revelation of himself and the ways of salvation (2 Timothy 3:15-16). Acquire and use study aids such as one or more study Bibles. I recommend The Apologetics Study Bible, The Reformation Study Bible, The NET Bible, and The NIV Study Bible. Of course, there are many other tools such as commentaries and other helps. The excellent commentaries of John Calvin and Matthew Henry are available online.
Be involved in a Bible-believing and Bible-teaching local church, and seek to serve through what you have learned. Biblically, we are responsible to use what we know wisely and for the glory of God. We should not hide our gifts under a table, but employ them to build up the church and witness to the world (Matthew 5; Ephesians 4:15). Specifically:
Develop adult education classes on the Christian worldview, biblical interpretation, theology, apologetics, and social issues.
Make sure your church has some way of preparing high school students for college. Many churched teenagers either put aside their Christian convictions or lose them during this time. For how high school students in the church tend to think, see Christian Smith, Soul Searching. Also consult the essay “Faithful Christianity in College” by Douglas Groothuis and Sarah Geis at: http://www.patheos.com/blogs/philosophicalfragments/2013/04/09/faithful-christianity-in-college/
Be involved as a mentor to those who can benefit from your gifts. Try to find a suitable mentor for yourself as well (Proverbs 27:17; 2 Timothy 2:2).
Develop your skills at speaking, teaching, and conversation. American linguistic culture is ugly, sloppy, and lazy. Instead of blending with the inarticulate herd, broaden your vocabulary, work on articulation, and listen to the people with which you are speaking. On writing, see the classic Elements of Style by Stunk and White. On public speaking, see Stand Like Lincoln, Speak Like Churchill by James Humes. Consider joining a Toastmasters club to refine your speaking skills.
Read thoughtful Christian books, both classic and contemporary. While we often emphasize popular books, we should not forget time-tested classics written by Augustine, Calvin, Pascal, and Jonathan Edwards. Twentieth-century writers such as G. K. Chesterton, C. S. Lewis, John Stott, J. I. Packer, Francis Schaeffer, James Sire, and Os Guinness make for hearty and rewarding reading as well.
Certain periodicals are also edifying. For keeping the pulse of contemporary evangelicalism, see Christianity Today. Political and cultural issues are carefully addressed in First Things, which now has a rather strong Catholic focus. To stay abreast of cults, religious movements, apologetics, and ethics read The Christian Research Journal. Relevant is a popular magazine, which is aimed at millennials. However, I find it a bit trendy and superficial.
Be aware of secular culture and non-Christian religious expressions through your reading of periodicals and books. I also read the Sunday New York Times and The New Yorker for sophisticated secular views—and, in the latter case, for their superb cartoons. Commentary is excellent for conservative Jewish views. This is a resource for discerning what non-Christian books you should read, as is The New York Times book review. I also check Harpers, The Atlantic, Rolling Stone, Time Magazine, and Wired to look for significant articles. I find browsing at bookstores especially helpful, if you can find a brick and mortar bookstore. I am grateful that the Denver area has three locations of The Tattered Cover Bookstore.
Carefully and prayerfully consider your use of all electronic communications media. These often sap our knowledge and divert us from godly habits of the heart. Consider engaging in a protracted media abstention in which you eliminate a commonly-used electronic system for a week to ten days. It will profoundly change your view of technology. See my book, The Soul in Cyberspace. For my more recent thoughts see my interview with Tim Challies at: http://www.crosswalk.com/blogs/challies/the-soul-in-cyberspace-an-interview-with-douglas-groothuis-11603254.html Consider also the thoughtful, secular book, Hamlet’s Blackberry. For a broader historical and culture critique read Neil Postman’s magisterial work, Technopoly: The Surrender of Culture to Technology. The best book on television is Neil Postman, Amusing Ourselves to Death. See also my article in The Christian Research Journal, “Understanding Social Media” at: http://www.equip.org/PDF/JAF2333.pdf. For a more scholarly paper, see Douglas Groothuis, “Christian Scholarship and the Philosophical Analysis of Cyberspace Technologies,” (Journal of the Evangelical Theological Society, 4 14 (December 1998): 631-640. This is on line at http://www.etsjets.org/files/JETS-PDFs/41/41-4/41-4-pp631-640-JETS.pdf.
Listen to thoughtful radio programs and podcasts. Many gifted Christian teachers and preachers can be heard in this manner. Redeem the time by listening to them in your car, or while exercising, or when you cannot do anything else, such as when you are ill. An excellent source of cultural criticism from a Christian or Christian-friendly viewpoint is Mars Hill Audio, hosted by Ken Myers, author of All God’s Children and Blue Suede Shoes: Christians and Popular Culture (Eerdmans, 1989). Some audio books of thoughtful books are available for purchase or from a library.
Take periods of time—either short or long—for silence. Our culture is too noisy and over-stimulated. We need quiet to compose our bodies and souls before God in cognitive meditation, prayer, and rest. As Ecclesiastes says, there is a time to tear and a time to mend, a time to be silent and a time to speak (3:7; see also Habakkuk 2:20).
Consider Denver Seminary for further education. I head the MA in Apologetics and Ethics. We also offer a Certificate in Apologetics and Ethics (10 semester hours). See https://denverseminary.edu/academics/masters-level-certificates/ for more information.
As someone who has been laboring to develop a Christian mind since I became a Christian in 1976, I challenge you to think well for the cause of Christ and to even out-think the world for Christ!